It is well known in the art to provide an antireflective layer on the surface of an optical element to minimize or eliminate losses through Fresnel reflections occurring when light is transmitted through an interface between two different media, for example glass and air. The end faces of optical fibers and the surface of lenses of any size are two examples of optical elements typically requiring an antireflective layer.
It is known in the art to apply an antireflective treatment involving the deposition of antireflective coatings on an interface of an optical element. This technique is based on the application of multilayer interference structures with alternating high and low refractive indices leading to a surface having a low reflectivity. Another technique known in the art involves patterning the interface of an optical element to provide sub-wavelength structures. This technique mimics to property of a moth's eye, which includes a natural nanostructured film preventing reflections. As known in the art, multiple structures of dimensions and periodicity smaller than half the wavelength of light crossing the interface can provide a refractive index gradient which essentially removes the reflection inducing transition at the interface.
Antireflective treatments on optical elements can be challenging to implement. For instance, the equipment needed to perform the deposition of antireflective coatings can be expensive and the deposition process itself can be time consuming. Furthermore, formation of fine sub-wavelength structures on an optical interface requires sophisticated manufacturing techniques such as interference lithography, which are typically costly to undertake and can be both energy and time consuming without achieving repeatedly the desired results.
Thus, there is a need for a more affordable and practical manufacturing method to form a textured surface on an interface of an optical element.